Electrical control system



Feb. 2, 1937. R R, BAKE 2,069,516

ELECTRICAL CONTROL SYSTEM Filed May 1, 1935 2 Sheets-Sheet l WITNESSES: 1 INVENTOR R652 ESQ/@97 BY 6M5.

ATTORNEY Feb. 2, 1937. R. R. BAKER 2,069,516

ELECTRICAL CONTROL SYSTEM Filed May 1, 1955 2 Sheets-Sheet 2 INVENTdR Restiafimker.

ATT" QNEY WITNESSES:

memes Feb. 2, 1 31 A 2,069,516

UNITED STATES PATENT OFFICE ELECTRICAL CONTROL SYSTEM Rest R. Baker, Swissvale, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application May 1, 1935, Serial No. 19,240

2 Claims. (Cl. 172-239) My invention relates to electrical control sysmachine element in any suitable manner and terns for electrical motors or other electrical demade responsive to the movement of the machine vices. element. This control means 30 is provided with More particularly, my invention relates to sysa pair of coils 29 and 50 and an armature held 5 tems of control for effecting any selected angular in the position shown by a pair of springs. The 5 movement of a motor shaft, or any selected poslcontrol means 30 merely illustrates one emboditional change of a device, intermittently, wherement but in fact may embody any kind of reguby hunting is prevented. lator or device responsive to the operating char- In certain devices where an operating element acteristics of a machine. It is only necessary of a machine may deviate from a desired path tha t e Control ns 30 ay fImCtiOII as 10118 10 of movement or mode of operation, it is desirable as a certain element of a machine is not in its to reestablish the correct movement or mode of desired operating position or is not performing operation. With the ordinary devices or reguits desired mode of operation. lators utilized heretofore difficulty is encountered The motor 42, which is to be controlled in its in stopping the regulating or controlling efiect direction of operation, is provided with a pair 15 when the desired mode of operation is reestabof directional contactors 35 and 53 which may lished. be operated intermittently by a pair of time limit One object of my invention is to provide for devices l8 and IS. The system of control as a controlling the operation of a machine element, whole is such that when the control means 30 or an electric motor only to such an extent as to is energized or caused to operate by reason of a 20 compensate for the deviation of the machine eledeviation from a desired position of a certain ment, or the motor shaft, from its desired operamachine element acting on the device 30, one of tion. the directional contactors, depending upon the Another object of my invention is to limit the operation of the control means 30, will be caused compensating efiect of a control for a machine to operate. The particular directional contactor 5 element by a measure of the deviation of the elethat is caused to operate remains energized for ment from its desired position or mode of operaa short interval of time determined by the time tion. limit device l9. Assoon as the time limit device Another and more specific object of my invenl9 operates to deenergize the directional con- 30 tion is to limit the total angular movement of tactor, it also causes the deenergization of the 30 a motor shaft, for any one control cycle, by the time limit device I8 which is adjusted normally value of the deviation of a certain machine eleto have a time constant somewhat larger than ment from a desired operating position. the time constant of the time limit device IS.

A still further object of my invention is to The time limit device l8, however, causes a re- :5 intermittently effect the operation of a motor energization of the time limit device l9 and thus 5 for a sufficient number of times and amounts of a reenergization of the previously energized direcangular rotation until the total angular change tional contactor.

of the motor shaft is proportional to the devia- The total efiect, therefore, on motor 42 is to tion of a machine element from a desired mode cause that motor to operate intermittently until 441 of operation. the control means 30 is no longer effected by Other objects and advantages of my invention the machine element which is not in its desired Will beCOme more pp from a u y of the operating position. Normally, the respective time following specification when considered in conconstants of the time limit devices are so adjunction with the accompanying dr w n in J'usted that the motor will be caused to operate which: for a comparatively short interval of time and 45 Fi ure l is a dia ramm tic howing of my then be at rest for a slightly larger interval of invention, and time and then again operate for a short interval g. 2 is a diagram w g of a pecifi of time. This cycle of operation is repeated until application of my invention. the motor has moved through an angle deter- Referring more particularly to Fig. 1 of the mined by the extent of deviation of the machine 50.

drawings, the reference character 42 designates element, the position of which is to be controlled. a reversible motor which adapted to operate The motor 42 is suitably interconnected with some device, the position or mode of operation repositioning means for the machine element, so of which is tobe controlled. A regulating device. that the machine element is repositioned to its or;cont'rol means 30 is interconnected with a normal operating position and its normal mode-of 56 operation is reestablished. From the foregoing disclosure, it is apparent that there will be no hunting of the motor 42.

A better understanding of the novel features of my invention can probably be had from a study of the sequence of operation.

Assuming that conductors I and I are suitably energized. Such being the case and the control means 39 being in the position indicated, energized circuits will be established from conductor I through conductor 2, contact members 3, conductors 4 and 48 through the magnetizing coil 5 of the time limit device I9 and resistor 6 to the conductor I.

Further circuits are also established from the conductor I through conductor 8, resistor 9 neutralizing coil III of the time limit device I8 and the adjustable resistor II connected in parallel with the neutralizing coil I0 and conductor I3 to the energized conductor 1. A circuit is also established from the energized conductor 8 through resistor I4, neutralizing coil I5 and adjustable resistor I6 connected in parallel with the neutralizing-coil I5 and conductor I'I to the conductor I. A still further circuit is established from conductor I through resistor 20, magnetizing coil H of the time limit device I8, conductor 22, contact fingers 23 and 25 bridged by the segment 24 on the armature of the time limit device I9, contact finger 26 and conductor 28 to the energized conductor I. Since both the magnetiz ing coils for the time limit devices I8 and I9 are energized, the armatures of these devices will be in the position shown.

If the control means 38, responsive to the deviation of a certain machine element from a normal operating position or from a selected mode of operation, is energized, then circuits will be established for the directional contactors depending upon the direction of deviation of the machine element from its desired operating position or mode of operation.

If the coil 29 of the control means 30 is energized, the contact members 32 thereof are closed and a circuit is established from conductor I through contact members 32, conductor 33, actuating coil 34 of directional contactor 35, contact fingers 36 and 26 bridged by the segment 21 and conductor 28 to the energized conductor I.

The energization of the actuating coil 34 of the directional contactor 35 will cause the closing of the contact members 31, thereby establishing a circuit for the motor 42, which circuit may be traced from the conductor I through a suitable accelerating resistor 40, which may be controlled in resistance value in any desired manner, through the armature H and field winding 43 of the motor 42, contact members 31 to the energized conductor 1. The motor 42 will thus be caused to operate in a given direction. It should be noted that the mechanical interlock 38 pivoted at 39 prevents the possibility of the closure of the directional contactor 53 at the same time the directional contactor 35 operates.

As soon as the control means 30 has become means 45, the circuit for the actuating coil 34 for the directional contactor 35 will be opened at the segment 21 and the operation of motor 42 will be stopped.

The opening of the circuit at contact fingers 23 and 25 causes the deenergization of the magnetizing coil 2| of the time limit device I8. This device will, therefore, release its armature a definite time interval after the deenergization of the coil 2I. The length of the time interval will, of course, be determined by the short circuit coil 60, the neutralizing coil I0 and the adjustment of the adjustable spring means 6|.

As soon as the armature of the time limit device I8 is released, the magnetizing coil 5 of the 1 time limit device I9 is r'eenergized by a circuit which may be traced from the conductor I through conductor 8, contact fingers 4I bridged by the segment 46, conductor 48, magnetizing coil 5 and resistor 5 to the energized conductor I. The time limit device I9 will, therefore, immediately close the circuit for the actuating coil 34 at the segment 21 and also close the circuit for the magnetizing coil 2I at the segment 24. The motor 42 will again be caused to operate for a short interval of time. After the expiration of such short time interval, the time limit device I8 will again be deenergized and the cycle will stant the ener'gization is removed from coil 29,

namely, the instant the machine element controlling the energization of coil 29 has taken its normal position, contact members 32 will be opened and the directional contactor 35 can no longer be energized. Further contact members 3 will close, therefore, establishing an energizing circuit for the magnetizingcoil 5 independent of the position of the armature of the time'limit device I8. The position of the apparatus will be exactly as shown in Fig. 1, and thus in condition to repeat its cycle of operation should the machine element controlling the energization of the control means 30 deviate from its desired operating position or mode of operation.

If the machine element, or motor, or whatever the device may be, should deviate in a direction opposite to that assumed in the cycle of operation hereinbefore discussed, then coil 50 would be energized closing the contact members 5|, thereby energizing the actuating coil 52 of the directional contactor 53. Contact members 54 are closed to cause the motor to operate in a direction opposite to that hereinbefore assumed. The motor 42 will thus intermittently effect its compensation or repositioning of the machine element to its original position, as hereinbefore explained.

Fig. 2 of the drawings shows a specific application of my invention to the control of a Fourdrinier wire of a paper machine. This Fourdrinier wire is indicated by the reference character I08 and is adapted to traverse a plurality of rolls of which two of them are indicated by the reference characters I00 and I05.

In the art of paper making, mechanical means ondary of the transformer are provided to maintain the Fourdrinier wire in a given position or a given path of travel on the guide roll or rolls. Such devices are needed because the wire has a normal habit of meandering from side to side on the guide rolls. Such mechanical devices require considerable actuating force from the wire with the result that the wire becomes frayed at the edges and serious breakage may thus result to shorten theuseful life of the wire.

My control system is well adapted to control the relative position of the guide rolls so as to maintain'the Fourdrinier wire in a given path of travel. The control means shown in Fig. 2 corresponding to the control means 30 shown in Fig. 1, comprises a pair of photo-cells H4 and H5 and a pair of lights H2 and H3 associated with these respective photo-cells, disposed at the respective edges of the Fourdrinier wire. The photo-cells are suitably interconnected with electronic means I20 and I2I, which, in turn, control the actuating windings I22 and I23 of the control contactors I24 and I25. The windings I22 and I23 in a sense correspond to the windings 29 and 50 of the control means 30 shown in Fig. 1. 1

To suitably energize the various elements of my control system, I show a pair of buses H6 and I I1 which are adapted to energize transformers I I8 and II9. The right-hand terminal of the secondary of transformer H8 is interconnected with the anode I33 of the electronic device I20 and is interconnected with the cathode I3I from the left-hand terminal through the actuating coil I22 and the resistor I30. The left-hand terminal of the secondary of the transformer H8, by the circuit mentioned, is also interconnected with the cathode I35 of the photo-electric cell I I4 and the grid I32 of the electronic device I20, this interconnection being effected through the capaci-- torv I34. The anode I36 of the photo-electric cell H4 is connected directly to the right-hand terminal of the secondary of the transformer H8.

The left-hand terminal of the secondary of the transformer H3 is directly connected to the anodes I40 and I43 of the devices I2I and H5, respectively. The right-hand terminal of the sec- II3 is connected through the actuating coil I23 and resistor I31 to the cathode I38 of the electronic device I2I. The grid I39 of the electronic device I2I and the cathode I42 of the photo-electric cell II5 are interconnected with the right-hand terminal of the secondary of thetransiormer II9 through the capacitor Hi. The sources of light, namely II2 and-H3, are connected directly across the buses H6 and H1.

To drive the rollers I00 and I05, representing but two of a considerable number of rollers, a main motor I23 is energized from a suitable source through the controller I28 and the line contactor I 50.

To maintain the Fourdrinier wire or web I06 in a given path of travel, the roller I00 is provided with a pivotal hearing at the right pivoting about the point I02 and at the left has the bearing I01 movable in the guide I03 by the reversible motor I04. By suitably controlling the direction and extent of operation of the motor I 04, the Fourdrinier wire I06 or any other web to be controlled may be maintained in a given desired path of travel. However. with my special control such repositioning of the Fourdrinier wire is accomplished by intermittentoperatlon o! the motor I04, so that the correcting eiiect is accomplished in small increments, the sum of which is a direct measure of the amount of deviation of the web or Fourdrinier I 06 from its desired path of travel.

To accomplish this desired operation, the directional contactors I08 and I09 are controlled by the control contactors I 24 and I25 and the time limit devices I80 and 280.

A better understanding of the advantages and novel results of my invention can probably be had from a study of a typical sequence of operation when it is assumed that the Fourdrinier wire I06 has deviated from its desired path of travel in one or the other direction by any amount determined by its own habits of meandering.

If buses H0 and III are suitably energized, energizing circuits are established from bus IIO through contact members I64 and I65, resistor I66, magnetizing coil I61 of the time limit device I80 to the energizing bus III. Another circuit is established from the bus I I0 through conductor I68, resistor I69, adjustable resistor I10 and neutralizing coil I 1| connected in parallel thereto to the bus III. The neutralizing coil "I has a negligible effect relative to the effect of the coil I 61. However, when coil I61 is deenergized, the neutralizing coil acting in conjunction with the short circuit winding I12 and the spring assembly I13 provides for the opening of the contact members I53 and I14 a predetermined interval of time after the'deenergization of the magnetizing coil I61.

Further circuits may be traced from the bus I I0 through resistor I 15, magnetizing coil I16 and contact members I14 to the bus I I I. A further circuit may be traced from the bus IIO through the resistor I8I, the neutralizing coil I83 connected in parallel to an adjustable resistor I82 and conductors I85 and 186 to the bus III. The neutralizing coil I83 has a negligible effect rela- 'tive to the effect of the magnetizing coil I16.

time constant of the time limit device 280 is adjusted to be somewhat longer than the time constant for the time limit device I80, thereby providing a period of non-operation of the motor I04 greater than its period of operation when the web is to be adjusted or repositioned to its desired path of travel.

Assuming that the attendant wishes to start the machine, he actuates the starting push button I44, thereby closing the contact members I to thus establish a circuit from the bus IIO through the contact members I41 and I45, the actuating coil I43 of the line contactor I to the bus III. Operation of the line contactor I50 closes the contact members I5I and by suitable means embodied in the controller I28 starts the motor I29 for driving the paper making machine. Closure of the contact members I5I does not at this stage accomplish any useful operation other than to establish a closed circuit for the motor I 04 when either one of the directional contactors I08 or I03 are operated by the control contactors I24 and I25. The contactors I08 and I03 are provided with an interlock I26 to prevent the possibility of both contactors being operated at the same time.

If it be assumed that theFourdrinier wire I06 has meandered to intercept the light passing from the source of light I I2 to the photo-cell I I4, the bias on the grid I32 for the electronic device I20 will be so changed that the coil I22 becomes deenergized, thereby dropping its armature, opening the contact members I56, and closing the contact members I55. The closure of the contact members I55 establishes a circuit from the bus I I through the contact members I 55 and I6I, actuating coil I62 of the directional contactor I09 and contact members I59 to the bus II I..

The moment the directional contactor I09 is energized, its contact members 264 are closed and the motor I04 is energized by a circuit which may be traced from the bus IIO' through the starting resistor I6I, armature I62, field winding I63, contact members 264 and I5I to the bus III.

The motor I04 will thus operate to shift the bearing I01 in such a direction as to efl'ect a repositioning of the Fourdrinier wire or web I06 to its desired path ,of travel. However, my system of control is so designed that any one operation of the motor is not likely to effect a complete repositioning of the web I06 to its desired path of travel but the correction is effected by intermittent operation of the motor I04. This is accomplished by the cooperative actionof the control contactors I24 and I25 and the time limit devices I80 and 280.

The deenergization of the actuating coil I22 as hereinbefore explained opens the contact members I64 and deenergizes the magnetizing coil I61. The directional contactor I09 will thus remain energized for only a comparatively short interval of time depending upon the time constant of the time limit device I80 and will then be deenergized by the opening of the contact members I59.

The downward movement of the armature for the time limit device I80 opens the contact members I14, thereby deenergizing the magnetizing coil I16. After a definite time interval which is usually chosen to be longer for the device 280 than for the device I80, the contact members I81 will close thereby reenergizing the magnetizing winding I 61 independent for the time being of the position of the armature of the control contactor I24.

The magnetizing coil I61 being thus reenergized effects the closing of the contact members I I59 and thus the reclosing of the contact members 264 of the directional contactor I09. The motor I04 will thus be again set in operation but will remain in operation only a short interval of time depending upon the time constant of the time limit device I80, which will again be immediately deenergized by the opening of contact members I81 by reason of the reenergization of the magnetizing coil I16 through the contact members I14. It will thus be apparent that the motor I04 will operate for a very short interval of time, rest or be prevented from operating for a short interval of time and then again oper-ate and so on until the web has been shifted so that light is no longer intercepted from the source of light II2, whereupon the contact members I64 will close, reenergizing the magnetizing coil I61 independent of the position of the armature of the time limit device 280 but the contact members I55 will also open, thereby disconnecting the motor I04 from the buses- H0 and III.

If the web or Fourdrinier wire I06 meanders toward the right, the cycle of operation will be exactly as explained before but will be initiated in its operation by the control contactor I25 which will close the contact members I51 energizing the coil I58 of the directional contactor I08 and thus effect or cause the closure of contact members I60. The contact members I65 will also open, thereby starting the time limit device I80 which will, in turn, initiate the operation of the time limit device 280 to thus eflect the intermittent operation of the motor I04. For any one deviation of the Fourdrinier I06, the motor I04 will thus be caused to operate intermittently until the web has been repositioned to its desired path of travel but will not operate to a greater extent to thus cause a' hunting of the motor I04.

If any one or two, or all three of the devices such as the lights, the photo-cells or electronic devices fail at one edge of the web the corresponding devices at the other edge alone assume the control duty, whereas if two devices on opposite sides fail, then the actuating coils I22 and I23 will both be deenergized, closing contact members I54 and I88 to thus establish a circuit for the danger signal I90 and an energizing circuit for the operating means I89 of the time limit device I48, which is so designed to open the contact members I41 after a definite interval of time determined by the adjustment of dashpot I21, thereby deenergizing the actuating coil I49 which will thus cause the opening of the contact members I5I and also stop the main motor I29.

While I have in Fig. 2 disclosed my invention in conjunction with aparticular application to a paper making machine, it is readily apparent that my invention is general, as shown in Fig. 1, and is not limited to a particular application but that the position or mode of operation 01' a machine element, regardless of the type of machine that may be utilized to deenergize the control means may be controlled by intermittent operation of a motor such as I04, or 42, which intermittent operation will continue up to and until the machine element, the position of which is to be controlled is replaced to its desired operating position.

I am, of course, aware that others particu- I larly after having had the benefit of the teachings of my invention may readily devise other circuit diagrams for accomplishing the novel features hereinbefore set forth, but I do not wish to be limited to the specific showings herein made or illustrated in the drawings but wish to be limited only by the pertinent prior art and the scope of the claims hereto appended.

I claim as my invention:

1. In a system of control for a motor controlling the operation of a machine element having the habit of departing from a desired mode of operation, in combination, a motor, a source of energy, switching means adapted to connect the motor to the source of energy, electromagnetic inductive time limit relays adapted to energize the switching means for a predetermined interval of time and adapted to deenergize the switching means for a predetermined interval of time, and means responsive to a machine element having the habit of departing from a desired mode of operation adapted to cause the alternate operation of'said last named means by a number of alternations determined by the departure of the machine element from the desired mode of operation.

2. In a system of control for controlling the mode of operation of a machine element which may depart from its desired mode of operation, in combination, a reversible motor, a source of energy, a pair of reversing switches adapted respectively to connect the motor to the source of energy for one or another direction of operation, electromagnetic inductive time limit relays adapt ed to energize either one of said reversing switches for a predetermined interval of time and adapted to deenergize either one of the reversing switches for a predetermined interval of time, and means responsive to the departure of the machine element from its desired mode of operation adapted to select the particular reversing switch to be operated by said time limit devices and means adapted to cause alternate operation of the time limit means to thus effect said energization and deenergization of the reversing switch selected to thus intermittently cause the operation of the reversing motor.

REST R. BAKER. 

